Field of the Invention
The present invention relates to a method of manufacturing high hardness memebers which may be used for various kinds of tools, machines, and the like.
Description of the Prior Art
As a material for cutting tools, which require a high hardness, and for abrasion-resistant tools, such as various kinds of dies and pressed tools, there has been known in the past a hard material of WC-CO composition. Because this material is hard to work, it is not easy to form the material by casting, forging, etc. For this reason, the process of powder metallurgy is employed. Since, however, powder metallurgy requires strict control over the nature of the raw material powder and the particle size of carbide, the carbon content, and the type of the sintered alloy, there has been a demand for a high hardness material which is inexpensive as well as easy to work with that does not use powder metallurgy processes.
On the other hand, a high hardness iron-based alloy, high speed steel, which is machine workable, has been in existence for some time. However, high speed steel has a lower hardness which is less than about one-half of that of hard metals, so an iron-based alloy with a higher hardness has been desired.
Intermetallic compounds have also been known as high hardness materials, but they have a problem in that they are extremely difficult to work elastically because of their brittleness.
In addition, there has been known a method in which a high hardness member is obtained by subjecting an easy to work alloy to a surface treatment after forming. For such surface treatment, two methods are known: ion implantation and plating. The ion implantation method has a disadvantage in that sufficient hardness cannot be obtained because the ion implanted layer tends to be broken under loading due to the very small thickness of the layer. The plating method has a problem in that the plating of a high hardness alloy tends to peel off under laoding It is an object of the present invention to provide a method of making a high hardness product which is not subject to the foregoing disadvantages.
These and other objects, features and advantages of the present invention will be more apparent from the following description of a preferred embodiment, taken in conjunction with the accompanying drawing.